In communication technologies, such as wireless communication, various digital filtering functions are required in digitally processing received signals to extract data. Filter processors or processing units are used for filtering the received signals and are selected based on the filtering requirements of the wireless communication technology. Filtering may be done on an analog signal or a digital signal, typically using an infinite impulse response (IIR) filter or a finite impulse response (FIR) filter.
Various filter components may be combined to provide an overall desired transfer function to be applied to the received signals. The transfer function of a filter may be a first order, or higher order, transfer function. Typically, filters are configurable by changing values of parameters such as coefficients of the transfer function.
Although varying the coefficients of filters allows the characteristic of the filter to be tuned for different conditions, it is not possible to modify the overall topology of the filter. The possible connections between filter components defining the overall filter topology is set at design time, or when configuring the processor such as when powering on the processor in the case of a field programmable gate array (FPGA). It has not been possible to modify the overall filter topology of the filter to adequately adapt to a range or communication technologies in a single digital signal processing unit.
Therefore, there is a need for a filter processor capable of reconfiguring the filtering characteristics to adapt to a range of communication technologies.